Counterbore



Oct. 18, 1949. w. VAN BENSCHOTEN 2,485,077

COUNTERBORE Filed July 20, 1945 WALTER VAN BENSCHO TEN,

IN VEN TOR.

ATTORNE Patented Oct. 18, 1949 UNITED STATES PATENT OFFICE COUNTERBORE Walter Van Benschoten, Santa Monica, Calif.

Application July 20, 1945, Serial No. 606,167

2 Claims.

The invention relates to a counterbore and has for an object to simplify and improve the construction whereby different pilots and counterbore tools may be readily used with the same holder and in particular, whereby different tools or a selected tool may be assembled onto or removed from a holder-pilot unit with facility.

For further details of the invention reference may be made to the drawings wherein- Fig. 1 is a view in elevation of a counterbore according to the invention.

Fig. 2 is a partial sectional view through the lower part of the tool of Fig. 1.

Fig. 3 is a sectional view on line 3--3 of Fig. 2.

Fig. 4 is an exploded view of the tool of Fig. 1.

Referring in detail to the drawings, the holder I has a coaxial threaded ibOIB 2 to receive the threaded end 3 of a pilot 4. Various sizes of pilots may be used. The counterbore tool 5 slidingly fits the holder-pilot unit, so that the counterbore 5 can be assembled on or removed from the holder I and pilot 4 without removing pilot 4 from the holder I. Various sizes of counterbore tools like 5 can be used with the same holder and pilot.

The invention provides for assembling or removing the counterbore 5 with facility by providing for the application of pressure from the holder to the counterbore without thereby tightening the lock therebetween as in the case of a tapered shank and socket.

The counterbore tool 5 at its inner end is milled out, :to provide a socket or recess 6 while leaving projections I1 and I8, the opposed inner walls [4 and I5 of which are parallel and flat, at opposite sides of the tool axis, to provide rotative engagement with the holder I. The lower end of holder I is cutaway to provide parallel flats I6, I6 which fit in recess 6 between the tool flats I4 and I5.

The recess 6 between projections I1, I8 has a shoulder or end I, extending in a plane at right angles to the tool axis. The end 8 of holder I bears on shoulder I, and extends between projections II, I8, the holder I being of smaller diameter than tool 5. Working pressure along the axis of holder l is applied to tool 5 by the end of holder I bearing on shoulder I.

An additional pressure surface across the axis is provided as follows. The height of the projections I! and I8 is greater than the height of holder flats I6, I6 and the opposite shoulders like Ill on holder I rest and fit in the opposite recesses like 1-) in the outer ends of projections I'I, I8 when the end of holder I fits between projections I1 and I8 and rests on the tool end or shoulder I. The periphery of the two recesses like 9, in a plane across the tool axis, lies on a circle havin a diameter slightly larger than the diameter of the body of holder I.

The tool 5 has a coaxial bore -I3 to slidingly fit the pilot 4.

The tool 5 is removably held in position on the holder I and on pilot 4 by a spring wire key l9, somewhat U shaped and having parallel legs 20, H which fit in parallel recesses 22, 23, each extending partly through one of the holder flats l6. l6 and partly through one of the tool flats I4, I 5. The lateral ends of recess 6 house the bight and esnds of wire key I9 within the periphery of tool The key I9 keeps the counterbore 5 from falling off from the holder I and pilot 4.

All of the non-circular ro'tative engagement flats I4, =I5, I6, I6 lie in planes parallel to the tool and holder axis, whereby they are not locked together when axial working pressure is applied to the holder I.

Various sizes of counterbore tools and pilots may be used with the same holder. Various other modifications may be made without departing from the spirit of the following claims.

I claim:

1. A counterbore comprising: a holder; a pilot; cooperating means on the pilot and in the holder, mounting the pilot coaxi-ally in the holder; a counterbore tool having an axial bore through which the pilot extends, said pilot having a projecting end portion of a diameter less than that of the bore, whereby the tool may be slipped over the pilot while the pilot remains mounted in the holder, said tool having a recess in which the end of said holder is received, and having a shoulder against which the end of said holder abuts, said holder and tool having interfitting flats disposed in planes parallel to and on opposite sides of the tool aXis and cooperating to transmit drive from the holder to the tool, and said holder and tool each having cooperating portions of key recesses opening into and parallel to the respective flats: and a U-shaped key having spaced legs received in the respective key recesses and having a, bight connecting said legs, said tool being cut away between corresponding ends of said key recesses to house said bight.

2. A counterbore comprising: a holder; a pilot extending coaxially therefrom; a counterbore tool having an axial bore through which the pilot extends,.said pilot having a projecting end portion of a diameter less than that of said bore, whereby the tool may be slipped over the pilot, said tool having a recess in which the end of said.

3 4 holder is received, and having a shoulder against which the end of said holder abuts, said holder REFERENCES CITED and tool having interfitting flats disposed in The following references are of record in the planes parallel to and on opposite sides of the tool file of this patent: axis and cooperating to transmit drive from the holder to the tool, :and said holder and tool each 5 UNITED STATES PATENTS having cooperating portions of key recesses open- Number Name Date ing into and parallel to the respective flats; and 1,285,869 Wineman Nov. 26, 1918 a. U-shaped key having spaced legs received in 1,461,462 Smith et al July 10, 1923 the respective key recesses and having a bighti 10 1,465,612. Morse Aug. 21, 1923 connecting said legs, said tool being cut away be- 1,886,177 Gairing Nov. 1, 1932 tween corresponding ends of said ke recesses to. 2,009,168 Dettmer July 23, 1935 house said 'bight.

WALTER VAN BENSCHOTEN; 

